upstream/mercurial-mirror Files · mercurial/cffi/mpatchbuild.py

revlog: new API to emit revision data...

revlog: new API to emit revision data I recently refactored changegroup generation code to make it more storage agnostic. I made significant progress. But there is still a bit of work to be done. Specifically: * Changegroup code is looking at low-level storage attributes to influence sorting. Sorting should be done at the storage layer. * The linknode lookup and sorting code for ellipsis is very complicated. * Linknodes are just generally wonky because e.g. file storage doesn't know how to translate a linkrev to a changelog node. * We regressed performance when introducing the request-response objects. Having thought about this problem a bit, I think I've come up with a better interface for emitting revision deltas. This commit defines and implements that interface. See the docstring in repository.py for more info. This API adds 3 notable features over the previous one. First, it defers node ordering to the storage implementation in the common case but allows overriding as necessary. We have a facility for requesting an exact ordering (used in ellipsis mode). We have another facility for storage order (used for changelog). Second, we have an argument specifying assumptions about parents revisions. This can be used to force a fulltext revision when we don't know the receiver has a parent revision to delta against. Third, we can control whether revision data is emitted. This makes the API suitable as a generic "index data retrieval" API as well as for producing revision deltas - possibly in the same operation! The new API is much simpler: we no longer need a complicated "request" object to encapsulate the delta generation request. I'm optimistic this will restore performance loss associated with emitrevisiondeltas(). Storage unit tests for the new API have been implemented. Future commits will port existing consumers of emitrevisiondeltas() to the new API then remove emitrevisiondeltas(). Differential Revision: https://phab.mercurial-scm.org/D4722

Yuya Nishihara - - Load All Authors

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             mpatchbuild.py
        
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      from __future__ import absolute_import

      import cffi

      import os

      ffi = cffi.FFI()

      mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), '..',

                                           'mpatch.c'))

      with open(mpatch_c) as f:

          ffi.set_source("mercurial.cffi._mpatch", f.read(),

                         include_dirs=["mercurial"])

      ffi.cdef("""

      struct mpatch_frag {

             int start, end, len;

             const char *data;

      };

      struct mpatch_flist {

             struct mpatch_frag *base, *head, *tail;

      };

      extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

      int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);

      ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);

      void mpatch_lfree(struct mpatch_flist *a);

      static int mpatch_apply(char *buf, const char *orig, size_t len,

                              struct mpatch_flist *l);

      struct mpatch_flist *mpatch_fold(void *bins,

                             struct mpatch_flist* (*get_next_item)(void*, ssize_t),

                             ssize_t start, ssize_t end);

      """)

      if __name__ == '__main__':

          ffi.compile()

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				from __future__ import absolute_import

				import cffi
				import os

				ffi = cffi.FFI()
				mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), '..',
				'mpatch.c'))
				with open(mpatch_c) as f:
				ffi.set_source("mercurial.cffi._mpatch", f.read(),
				include_dirs=["mercurial"])
				ffi.cdef("""

				struct mpatch_frag {
				int start, end, len;
				const char *data;
				};

				struct mpatch_flist {
				struct mpatch_frag base, head, *tail;
				};

				extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

				int mpatch_decode(const char bin, ssize_t len, struct mpatch_flist* res);
				ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
				void mpatch_lfree(struct mpatch_flist *a);
				static int mpatch_apply(char buf, const char orig, size_t len,
				struct mpatch_flist *l);
				struct mpatch_flist mpatch_fold(void bins,
				struct mpatch_flist* (get_next_item)(void, ssize_t),
				ssize_t start, ssize_t end);
				""")

				if __name__ == '__main__':
				ffi.compile()